I found an even better solution for .avi files! May even want to put it into the guide, heh heh.

I'm still having some trouble with .mkv files though. :/

No.

Nonononono. You shouldn't import lossy files into an editor (no matter how much your PC supports the codecs or not). Please. You should convert them to lossless with Avisynth (or at least clips) and THEN (and ONLY THEN) import them to your editor. Otherwise you're in for a screwed up import, screwed up export, sooner or later!

Lossy = there is INFO about your video MISSING. Lossless means that all the info is IN your file. You shouldn't ever edit with a file where there are some data missing!

Btw, I can download the Avisynth just fine from the site you linked. AND it's included in the guide I linked you, in the pack (here: link)